In recent years there has been increasing use of coated glass in the construction industry, especialy in spandrel and interior design applications, since such glass is substantially less expensive than conventional exterior materials such as brick and granite and presents aesthetically appealing design choices for interiors. Metallic coatings have been applied to enhance both the aesthetic appeal and reflective character of such glass, the latter conserving energy in air-conditioned buildings. Ceramic frit coatings have been used to color and to opacify such metal-coated glass. However, ceramic frit glass has several very serious drawbacks. One drawback lies in the tendency of ceramic frit-coated glass to become warped in the course of manufacture because of the high temperatures required to fire the glass. Another even more serious drawback is due to the presence of substantial amounts of lead in the ceramic frit coating composition. Lead, a toxic metal, requires special care in handling during ceramic frit coating processes and, in fact, its use in ceramic frit coating is now prohibited by regulations of the United States Environmental Protection Agency.
There is therefore a need in the art for a glass coating that enhances the tensile strength and energy conservation properties of construction or architectural grade glass, that can render the same opaque and impart color thereto, and that can withstand the elements, all without adding any hazardous materials to the environment. These needs and others are met by the process and resulting product of the present invention, which is summarized and described in detail below.